and many more benefits!

GMAT Club Timer Informer

Hi GMATClubber!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Hide Tags

Show Tags

16 Sep 2014, 00:59

1

00:00

A

B

C

D

E

Difficulty:

55% (hard)

Question Stats:

66%(00:58) correct 34%(01:31) wrong based on 86 sessions

HideShow timer Statistics

Although it would be unexpected for an attacking dragonfly to gain advantage by presenting itself openly, scientists observed that in 8 out of 15 inter-species battles between male dragonflies, the attackers did not prevent detection of their presence as they would from predators. Instead, the dragonflies employed a technique called “motion camouflage” by which they attacked openly, but in a straight line from a fixed object. The reaction times of their adversaries, who did not seem to realize they were approaching, were slowed significantly, and the attackers were victorious in each case.

Which of the following, if true, forms the best basis for at least a partial explanation of the success of motion camouflage in dragonfly battles?

A. The dragonflies attacking in a straight line moved more quickly than other dragonflies observed in battle, causing their adversaries’ reaction times to seem slow by comparison. B. The adversaries of the dragonflies, like scientists, do not expect to be attacked openly.C. Scientists record a lower success rate for dragonflies who attack using a zig-zag pattern, rather than a straight line attack.D. Scientists theorize that by remaining on a straight line with some landmark point, the attacking dragonfly remains stationary from the point of view of his adversary. E. Scientists discover inaccuracies in the devices used to measure reaction times of adversaries.

Show Tags

16 Sep 2014, 00:59

2

Official Solution:

Although it would be unexpected for an attacking dragonfly to gain advantage by presenting itself openly, scientists observed that in 8 out of 15 inter-species battles between male dragonflies, the attackers did not prevent detection of their presence as they would from predators. Instead, the dragonflies employed a technique called “motion camouflage” by which they attacked openly, but in a straight line from a fixed object. The reaction times of their adversaries, who did not seem to realize they were approaching, were slowed significantly, and the attackers were victorious in each case.

Which of the following, if true, forms the best basis for at least a partial explanation of the success of motion camouflage in dragonfly battles?

A. The dragonflies attacking in a straight line moved more quickly than other dragonflies observed in battle, causing their adversaries’ reaction times to seem slow by comparison. B. The adversaries of the dragonflies, like scientists, do not expect to be attacked openly.C. Scientists record a lower success rate for dragonflies who attack using a zig-zag pattern, rather than a straight line attack.D. Scientists theorize that by remaining on a straight line with some landmark point, the attacking dragonfly remains stationary from the point of view of his adversary. E. Scientists discover inaccuracies in the devices used to measure reaction times of adversaries.

Situation:Contrary to what might be expected, male dragonflies attack openly and are successful. Scientists call their technique “motion camouflage.”

Reasoning:Which point provides a basis for explaining this phenomenon?Discussion of male dragonflies in this passage centers around their use of camouflage, a technique used to manipulate what an adversary’s vision. Dragonflies use camouflage to hide from predators, but in the inter-species battles discussed in this passage, they do not hide, but present themselves openly. The correct answer will offer the best explanation for the way in which an open attack still manipulates an adversary’s vision.

This option does not account for the success of the “motion camouflage” technique.

The expectation discussed in the passage is that of the scientists; the expectations of the dragonflies would be impossible to determine, and are outside the scope of the passage.

A zig-zag pattern is not discussed in the passage; this observation would add little to an explanation of the success of an open attack.

The reason they can’t tell the attackers are moving is because they stay in basically the same place relative to a background object.

.This option would not negate the fact that dragonflies are consistently successful when they attack in the open.

Show Tags

Motion camouflage technique use straight line approach.So, Option A says...

Dragonflies using straight line approach moves more quickly and hence the adversaries get less time to save themselves.A is also giving partial explanation of the success of motion camouflage in dragonfly battles.

Show Tags

25 Sep 2016, 12:40

I don't agree with the explanation. They want an explanation to the success of the motion camouflage. Scientists theorize ..... this will be true according to the question. but what they theorize does not have to be true. so this is not adequate explanation. option a seems to make more sense.

Show Tags

25 Sep 2016, 12:45

1

Option D states that "scientists theorize...". while the fact that scientists theorize something has to be true as per the question. Isn't it possible that what they theorize might be wrong? Option A seems to be more accurate.

Show Tags

Motion camouflage technique use straight line approach.So, Option A says...

Dragonflies using straight line approach moves more quickly and hence the adversaries get less time to save themselves.A is also giving partial explanation of the success of motion camouflage in dragonfly battles.

Thanks in advance.

dnbhattacharya wrote:

Option D states that "scientists theorize...". while the fact that scientists theorize something has to be true as per the question. Isn't it possible that what they theorize might be wrong? Option A seems to be more accurate.

The conclusion states "......who did not seem to realize they were approaching... ". Option A does not explain this part. Moreover option A states that the reaction time seemed slow, but the passage states that the reaction time is actually slow. The scientists' perception of slowness is not a valid explanation for the success of the attacker.

As for option D, scientists' theories can be valid explanations, at least partially, for observed phenomena.